


Nagisa’s Fate

by Hisokas_s1sterdear



Category: Assassination Classroom
Genre: Multi, Tentacle Sex
Language: English
Status: In-Progress
Published: 2020-08-12
Updated: 2020-08-16
Packaged: 2021-03-05 19:13:33
Rating: Explicit
Warnings: Underage
Chapters: 3
Words: 2,651
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25860385
Author URL: https://archiveofourown.org/users/Hisokas_s1sterdear/pseuds/Hisokas_s1sterdear
Summary: This is my first work, so please don’t judge. Thanks! :)
Relationships: Nagisa/Koro-sensei
Kudos: 44





	1. What Happened To Koro Sensei.

**Author's Note:**

> This is my first work, so please don’t judge. Thanks! :)

What Happened To Koro Sensei.

Koro sensei’s eyes felt heavy, but not only his eyes, his entire body. He felt weak, limp, defeated. He had never felt so helpless before, other than that he couldn’t move. Slowly but surely he was able to open his eyes. The room was bright, too bright. Once his eyes had adjusted to the brightness he noticed he was strapped down to a table. 

“I can get out of this!, he thought, this is nothing for a monster with Mach 20 speed like me!”

Or so he thought, but his speed wasn’t able to free him in this situation. He was trapped.

“Shit” He cursed.

“Cursing now are we?” Said a deep voice from the corner of the room. Koro Sensei couldn’t see who he was.

“I’d have expected better from such an exemplary teacher like you.” Said the voice anew. 

“What do you want from me, why am I strapped down, and most importantly where am I, I need to get to school.” He seethed.

It was true, the last thing Koro Sensei remembered was flying to school before he blacked out and landed here.

“My, my asking so many questions today.” The voice spoke. 

“Well, since you’re asking... You’re in a government facility.  
Or... an abandoned one should I say. It’s working just fine again since I quit my old job working for the government as a scientist, and started running an underground experimental science lab.” The voice explained. 

Koro Sensei made a sound of frustration. Before he heared footsteps waking closer to him. Now, towering above him was a man with a mask.  
Koro Sensei narrowed his eyes at him.  
“Anyhow, the man continued, I already knew about you before quitting working for the government. To be fair if I hadn’t quit they would have just fired me, since they where on the verge of finding out I was a biiiit of a pedophile.” The man testified, with an unremorcefull tone.  
Koro Sensei did not look pleased with this information.

“So anyways, the man picked back up, I was mixing and experimenting around, when suddenly a great Idea popped into my head!” The man exclaimed.  
“To cut to the chase, I have created a serum that effects certain brain cells into liking children. The only way to stop this from happening is to cum into a child the age of 15.” 

“But I guess there really isn’t much of a difference if u do it or not!” The man laughed.

“You’re sick!” Koro sensei spit at him.

“Well you’re correct about that, but there’s nothing you can do about it now. Since i’ve already injected it into you.” The man said is a snickish voice. “Guess I should let you go now.” He sighed.

Koro sensei sighed in relieve. 

Suddenly the man pulled out a gun. Koro Sensei flinched, he was defenseless. Surely the man wouldn’t kill him, not after what he’d just said to him. 

“Oh don’t worry, the man reassured him, this gun isn’t for you.”

Koro Sensei looked confused, but before he could say anything the man cocked the gun, released him from the straps, and shot himself in the head.

Koro sensei was shocked, his eyes glued open, only grasping the situation when he heard employees rushing towards the room they where in. He decided that it was best he left the man there, even though it pained him, he decided to be selfish and flee. 

And with Mach 20 speed he was off to school. 

He was only a little late.  
During class his mind kept thinking about what had happened earlier. It was a really uneasy thought, but the more he thought about it the more he figured he might just enjoy it while he’s at it. He wondered if that was already the serum taking affect on his brain cells. But there was one student he’s always wanted to lay his hands on, or should he say tentacles. 

After class was over, he called the bluenette over to him.

“Yes Koro Sensei?” asked Nagisa.

“See me after school today.” He replied with a smile.

“Oh, okay Koror Sensei.” Nagisa answered, he wondered if he had done something wrong.


	2. Blue Haired Slut

**Summary for the Chapter:**

> Nagisa meets Koro Sensei after school and is surprised at what’s waiting for him.

**Notes for the Chapter:**

> There will be more Chapters coming, if the feedback is good so don’t worry. :)

Nagisa opened the door to the teachers office, where he was greeting with a smiling Koro Sensei already waiting for him.

“What did you want to talk about Koro Sensei?” The blue haired boy asked with a smile.

Koro Sensei took a deep breathe, and before Nagisa could ask what was wrong he was lifted in the air by several tentacles. 

“K-Koro Sensei, what are you doing? Nagisa looked confused.  
“Forgive me Nagisa.” Koro Sensei declared before slipping a tentacle up Nagisa’s shirt und cupping it around his nipple teasing it a bit.  
Nagisa gasped, a small moan slipping out.  
“Koro Sensei, stop it!” Nagisa Yelled, he was about to say something else but he was cut of by a tentacle making its way into his mouth.  
No matter how hard he pulled on it he couldn’t get the wet tentacle out of his mouth.  
He felt another tentacle making its way to his hole, slowly tracing the outsized before pushing itself inside of him. Nagisa moaned, he hated this so much, yet it was starting to feel good.  
“S-Sensei...” He moaned.  
The tentacle was making its way further into his mouth, it was moist, it almost felt good the way it was hitting the walls of his throat.  
Suddenly Nagisa noticed he was naked, his erection waving in the air. Another tentacle made its way up to his second nipple, slightly squeezing and rubbing it. It felt so good, that it made Nagisa moan. And another tentacle made its way to his ass, joined the other tentacle already pumping in and out of him. Slowly, together they stretched him out.  
“Koro Sensei, stop.” Nagisa Moaned. The octopus now pink just said,  
“Sorry Nagisa, no can do.” 

Nagisa whined as the two tentacles slipped out of him, his hard cock was also twitching as it hadn’t received any attention yet. Slowly the tentacles carried him over to the desk placing him across it, ass facing Koro Sensei. With Mach Speed Koro Sensei tied his hands and feet to the desk so he couldn’t escape.  
“You should be all stretched out now and ready for my cock.” Snickered Koro Sensei.

“Sensei, why are you doing this?” Nagisa asked with tears in his eyes. 

“That i’ll tell you later.” Koro Sensei explained as he whipped his ass with his tentacles over and over again. Nagisa’s cock was now dripping pre cum.  
“Please, please put it in Koro Sensei.” Nagisa whined and begged.

“Look at you, such a little slut, begging for his teachers cock. Praised Koro Sensei while slamming his cock into Nagisa’s tight ass.  
Nagisa let out a loud moan.  
“oh f-fuck!” Nagisa said under his breath trying to hold in the rest of his moans. 

“Be a good little slut and let out those dirty sounds of yours.” Koro Sensei demanded while ramming his ass with Mach 20 speed.

“Oh fuck, Koro Sensei!, Nagisa moaned, p-please my cock.” He pleaded and moaned.

“aww, does this little whores cock need attention?” Koro Sensei asked while twisting Nagisa’s nipples.

“hah, hng, yes, yes! This little sluts cock needs attention!” Nagisa moaned

Koro Sensei Laughed. “Only if I get to put this recording online.” Koro Sensei demanded.

Suddenly the idea of other people seeing him get rammed excited him so much as to where his cock started twitching even more.  
“Yes please, show the whole world what a slut I am.” Moaned Nagisa.  
And just like that a tentacle starting pumping his throbbing length.

The sensation of getting rammed at Mach 20 speed, his cock pumped, his nipples played with and being recorded was about to send him over the edge. 

“S-sensei, I need to cum.” Nagisa whined.

“Is that so, Koro sensei asked, surely you can wait until I fill you up with my seed.”

“Ah, Yes!” Nagisa moaned. “ I can wait!”

It didn’t take much for Koro Sensei to be sent over the edge too and cum inside of Nagisa. At the feeling of himself getting filled Nagisa came himself.

Nagisa lay on the desk panting, Koro sensei had already untied him and put his clothes back on.

“K-Koro Sensei, what was that?” Nagisa asked panting.

Koro Sensei took a deep breathe and started explaining.

Nagisa looked shocked, he felt bad for his teacher. He didn’t know what to say. But it did feel good, he loved it too much. “Koro Sensei, he finally said, you can use me, you can fuck me as much as you like!”

Koro Sensei eyes shot open. “Really Nagisa? Thank you so much! To be fair i’ve always wanted to fuck your tight ass, it feels so good!”

“I’ve never really thought about it, said Nagisa, but it feels so good to be someone’s slut, it feels so exciting my whole body is tingling! And um... I have a question Koro Sensei.” Nagisa admitted shyly.

“What is it Nagisa?” Asked Koro Sensei.

“Can, can we watch the video?” Nagisa requested.

“But of course we can Nagisa!” Koro Sensei answered gladly.

A smile spread across Nagisa’s face as he watched himself get railed like the little slut he is.


	3. NagisaXKoro-SenseiXRitsu

**Summary for the Chapter:**

> Nagisa gets a surprise from Koro Sensei.

**Notes for the Chapter:**

> I apologize for any spelling mistakes that may appear. :)

The school bell rang, and Nagisa was making his way toward the teachers office as he usually does after school. He was already trembling with excitement to get fucked by Koro Sensei again. As he walked in, Koro Sensei stood there grinning.  
“You’re in a good mood today Koro Sensei!” Nagisa smiled at him.  
“Indeed I am Nagisa-kun, because I have a surprise for you!” Koro sensei said with excitement.  
“Really?, Nagisa looked excited, I can’t wait to see what it is!”  
Koro Sensei smiled at him, as he moved closer to him. Softly putting a tentacle on his lips, and carefully tracing the shape.  
“Well then, everyone should be gone now.” Koro Sensei grinned. “Nagisa, would you please follow me into the classroom.”  
Sure enough Nagisa obliged and followed him into the classroom.  
Nagisa’s eyes widened with excitement. Before him stood a camera crew, with what looked to be very expensive equipment.  
“Well, Nagisa, Koro Sensei started, do you like it?” He asked the blue haired boy.  
“I love it Koro Sensei!” Nagisa said with joy flinging his arms around the octopus creature.

“We can’t wait to film such a fragile boy like you getting wrecked!” Said one man.  
“And by a tentacle creature at that!” Said another man. The rest of the crew nodded in agreement.

This excited Nagisa, as Koro Sensei could already see the bulge in the boys pants.

“But that’s not the only surprise I have for you.” added Koro Sensei.

Nagisa looked confused. Just as he was searching for an answer Ritsu turned on.

“Hi there Nagisa, she said, I will be helping Koro Sensei fuck you!” 

Nagisa’s eyes sparkled with joy. 

“Well then, let’s get started!” Beamed Koro Sensei. 

“And Action!” The cameras started rolling.

Koro Sensei wrapped his tentacles around Nagisa and lead him to stand in front of Ritsu.

“Give her a command Nagisa.” Koro Sensei whispered in his ear. Nagisa gulped, now fully aware the Koro Sensei had slipped two tentacles under his shirt and started stimulating his nipples. Nagisa let out a small moan.

“S-strip.” he commanded Ritsu.  
Ritsu did as she was told. Slowly she started taking of her clothes, until she was completely naked. She had quite a nice bust with nice pink nipples that where already hard, and a pink juicy looking pussy. Too bad Nagisa couldn’t fuck that, he thought.

“Give me another command Nagisa-Kun.” Ritsu smiled at him.

“Finger yourself.” Nagisa said this time, with more confidence.

Ritsu started to finger herself. Nagisa was about to reach for his throbbing member when he found a tentacle already on its way there, unzipping his pants, and pulling out his Cock. Slowly Koro Sensei started to jerk him off.

“F-fuck.” Nagisa moaned. This was too good to be true.  
“K-Koro Sensei, I wanna suck you off.” Nagisa said holding back his moans.  
“But of course Nagisa.” Koro Sensei said.  
But before he turned Nagisa around and forced him onto his knees, he swiftly took of Nagisa’s clothes. 

Nagisa carefully took Koro Sensei’s hard cock into his mouth, he was having trouble fitting it,  
but he was determined. He swirled his tongue around the tip, and bobbed his head down. Earning a moan from Koro Sensei, who was now his pink color. Not being able to fit more of his cock into his tight throat, he made up for the rest by using his hands. 

“You’re such a good little slut, taking my cock like that Nagisa!” applauded Koro Sensei.

Behind him Nagisa could hear whirring coming from Ritsu’s box and quite moans. Soon enough Nagisa felt a cool liquid drip deep into his ass. Ritsu has equipped herself with lubricant, and was now tracing the outside of Nagisa’s tight hole with a dildo. Soon enough she thrust the dildo into his tight ass, causing Nagisa to let out a loud moan, and a trail of smaller ones as she kept thrusting in and out of him. During all this Koro Sensei was still teasing his nipples. But to his dismay he stopped, when suddenly he felt a short and sharp pain on both of his nipples. He felt an unfamiliar weight on them. Soon enough he realized that Koro Sensei had pieced them. Koro Sensei’s tentacles tucked on the piercing going through Nagisa’s sore nipples, and the blue haired boy let out a very loud moan, grabbing everyone’s attention.

“Now you really look like a whore and a slut Nagisa, Koro Sensei praised, Not to mention your hairs ties are lose.”

Nagisa was blushing. He felt even more aroused at those words.

Suddenly Ritsu gripped him by the hair and pulled him away from koro Sensei cock, dildo still inside of him. She lifted him up, back leaning against her box, and she was pressing his legs open for everyone to see his throbbing member. Now that Nagisa could see again, he noticed that some of the camera crew was jerking off, occasionally giving him winks. This didn’t bother him though. 

“R-Ritsu, K-koro sensei, Nagisa moaned, I need to cum.”

“Not before I give you my cock.” Said Koro Sensei sternly.

Ritsu pulled the dildo out of Nagisa’s ass leaving a string of lube behind. You could still hear Ritsu’s whimpers, and moans. Nagisa was whimpering as well as his hole was now abandoned. Before Koro Sensei could slam into him at Mach 20 Speed, Ritsu held two vibrators onto his sore nipples, causing him to flinch and moan. His leaking cock was still being softly stroked by koro sensei’s tentacles.  
Nagisa jolted upwards, Koro Sensei’s cock rammed into his hole, making him moan uncontrollably. Being fucked at Mach 20 speed had never felt so good especially since every part of him was being stimulated, not to mention he was being filmed, which turned him on even more.

“Yes, hng, god fuck yes, Nagisa moaned, fuck me like the slut I am! Fuck my hole Koro Sense- hng aah! Make me your who- arg whore!”  
Nagisa moaned, he was getting close to release.  
Koro Sensei smirked at those words.  
“S-sensei..” Nagisa whined.

“Me too Nagisa..” Koro Sensei told him.  
And sure enough he soon felt the hot liquid being released inside him, coating his walls. Nagisa was sent into overdrive, letting out a series of loud ending moans, leaving him shaking.

After that Koro Sensei cleaned him up, and Ritsu shut down for the day. They watched the recorded footage before uploading it and all praised Nagisa for what a great whore and slut he is.  
That made Nagisa feel good.


End file.
